Splicing 220 Volt Wiring

How to Splice 220 Volt Electrical Wiring: Considerations when splicing 220 volt cable wiring in order to make the splice safe, accessible and makes sure the circuit maintains integrity.

Guide to Splicing 220 Volt WireElectrical Question: I’m splicing a new 8/3 cable with ground to an old 8/3 cable without a ground wire.

Should I join the new neutral white and ground with the old neutral white?

This electrical wiring question came from: Michael, a Electrician from Ooltewah, Tennessee.

Additional Comments: Love the website.

Dave’s Reply:
Thanks for your electrical wiring question Michael.

Splicing Electric Wire and Cables

Application: Splicing Electrical Wiring.
Skill Level: Intermediate to Advanced – Best performed by a Licensed Electrician.
Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester.
Estimated Time: Depends on the personal level experience and ability to work with tools and access to the wiring.
Precaution: Identify the circuit, turn it OFF and then Tag it with a Note before performing any wiring.
Notice: Installing additional electrical wiring should be done with a permit and inspected.
Special Materials: Properly sized wire connectors, anti-corrosion ointment, electrical tape, junction box and blank cover.

How to Splice 220 Volt 3Wire and 4Wire Cables

There are a few considerations which need to be addressed when splicing 220 volt cable wiring in order to make the splice safe, accessible and makes sure the circuit maintains integrity.

Safely Splicing 220 Volt Electrical Wires and Cables

If the original 8/3 cable is fed from the main electrical panel and the neutral wire of the original cable is insulated (it should be), then yes you can bond both the new cables neutral and the ground wires together with the old cable’s insulated neutral wire.

If the original 8/3 cable does not have an insulated neutral wire then you should only bond the ground wire of the new cable to the uninsulated wire from the original cable and the neutral wire of the new cable should be caped off with a wire connector at both ends and not used.

The issue here is that newer equipment such as a range may require a separate insulated neutral wire, which is in reality a current carrying wire or conductor which requires it to be insulated. If the new equipment states that it’s ground and neutral wires may be bonded together with the circuit ground wire at the attachment point of the equipment the that may be done.

A ground wire is not considered a current carrying conductor so it is not required to be insulated. The function of the ground wire is to bond the equipment to the main ground source which is at the main panel, so that in the event of an equipment failure the fault current will go directly to ground and will cause the circuit to trip off.

Hi Mike,
Splicing electrical wiring is permitted when it is done according to NEC codes, which include making the splice in an accessible junction box, using approved wiring connectors, and extending the circuit with the same type and size of electrical cable that is properly installed and protected.
I hope this helps,
Dave

I would like to move the 50 amp circuit that is in the top right of my panel to accommodate a generator lockout device. The problem is there is not enough wire to bring the breaker down to the bottom of the box where there is space. Can I use a junction box to extend the wire and extend the circuit.

I would like to relocate my circuit breaker box to a new location. My question is can I used the old circuit breaker box and convert that into a junction box to run my wires from there to the new circuit breaker box?

Hi Larry,
Using a breaker box or panel as a junction box is possible as long as the enclosure is treated the same as any other junction box, which would include sealing any unused openings and providing a solid cover that is securely fastened in place and resistant to the environment. The original panel components should be removed however the enclosure should be grounded.
I hope this helps,
Dave

Hi Dave, I have a 6 gauge 50 amp 220 volt wire out to my hot tub. I have gotten rid of my hot tub and wish to extend that wire (underground) to get 220 volt to my garage. I need to spice about 25′ ft longer. What type of spice box can I use. I plan to put the the wire underground in PVC conduit.
Thanks
Mike

Hi Mike,
The fiberglass splice boxes are great for this, and then a good splice kit, such as the 3M or other epoxy splice works very well.
Click the link below for more information:Underground Electrical Splice Box
I hope this helps,
Dave

I am remodeling a house my wife and I bought. She wants to take out a built in electric oven on one side of the kitchen and a gas cooktop on the other side and replace the gas cooktop with an electric range. My plan is to splice the 220 wiring for the built in to extend the circuit to the other side of the kitchen for an electrical access for the range. I have not taken out the built in yet and do not know at this point if it is 8 or 10 gauge wire. It would probably be easiest to simply cut the cable in the attic above the kitchen, add a box for splicing, then extend the wiring to the other side. Is it safe to do all of this? If not I can pull the existing wiring from the breaker box and replace with cable long enough for the project.

Hi Alan,
The way to approach this is to first look at what the circuit requirements are, and then look at what is available. You will need to know if a separate neutral wire is required for the required circuit power and if a neutral wire is available in the existing circuit wiring. Voltage and amperage ratings are essential to note. Keep in mind that if an existing circuit with a higher amperage rating will be used for a lower amperage purpose the circuit must be de-rated to provide the proper current protection. In other words you cannot safely provide 30 or 40 amps of power for a 20 amp device without adjusting the size of the circuit breaker to avoid overloading the circuit components.
I hope this helps,
Dave

While installing siding on my home a nail went thru a 220 volt wire which tripped off the circuit breaker. I removed the nail. Can I install a junction box and cut the wires apart and then make a splice with wire nuts?

Hi Orlena,
When an electrical cable has been damaged, an accessible splice is made using a junction box, cable connectors, the appropriate wire connectors, and then a blank cover is installed. If the junction box is metal then the box is grounded with the spliced circuit ground wires.
I hope this helps,
Dave